The present invention relates to a sliding roller bearing which is used when moving a movable portion of machine tools or other equipment rectilinearly in a precise manner.
A bearing device wherein numerous rollers roll in an elongated circular guide path formed by a track base and end caps is well known. The rollers have to be guided so that they roll correctly against the track surface. However, conventionally this type of bearing, which is provided only with retaining plates that contact the sides of the roller, cannot bear a load of large axial component force of the roller. Also there is proposed one which is provided by both retaining plates and guide plates which guide the lower surfaces of the roller. However, since such guide plates do not extend along the flat track surface up onto the curved surfaces of the end caps at both ends of the track base, a large frictional resistance exists at the curved surface portions, and thus accurate guiding is difficult.
It is accordingly an object of the present invention to obviate many of the deficiencies of the known prior art and to provide a novel sliding roller bearing structure. In the preferred embodiment, a hollow roller has a hollow pin for sustaining the roller, and thus a stepped roller is formed which increases load capacity. On the load side path of the roller, on both sides of the flat track surface and up onto the curved transfer portions of the end caps, there is provided a pair of guide plates having an external shape conforming to the locus of the internally moving hollow pin, thus permitting accurate guiding of the stepped rollers. The track base and the guide plates are made separately, thus allowing the surfaces contacting the rollers to be made with high accuracy and good surface finish at low manufacturing cost.
These and many other objects and advantages will be apparent from the claims and from the detailed description when read in connection with the drawings.